1. Field of the Invention
The present invention relates to a continuous liquid phase process for the preparation of tetraphosphorus polysulfides and, in particular, P.sub.4 S.sub.10.
This invention also relates to particular apparatus for carrying out the above process.
2. Description of the Prior Art
It is known to this art that the preparation of P.sub.4 S.sub.10 from liquid sulfur and liquid phosphorus, at a temperature ranging from 250.degree. C. to 515.degree. C., entails a strongly exothermic reaction.
U.S. Pat. No. 2,794,705 indicates that this reaction may be carried out in an unagitated reactor by introducing liquid phosphorus and liquid sulfur into a mass of P.sub.4 S.sub.10 maintained molten (515.degree. C.) in a vessel. The heat generated by the reaction is used to vaporize the P.sub.4 S.sub.10 formed.
Such a process presents a certain number of disadvantages. Due to the high viscosity of the medium--P.sub.4 S.sub.10 has range of high viscosity above its melting point--the heat generated is poorly distributed; this results in delayed boiling and superheating of the product. Said super-heating is manifested by powerful surges capable of damaging the reactor and its associated apparatus or of degrading the final product.